Suggest one more option for sample-config

I would like to suggest (and only suggest) that option for having
pages stored by group is shown in the sample-config ?
I think it is a choice which is best made as soon as possible when
starting a project.

Thus, maybe, something like this (at the right place) :

## Default is to save all pages in wiki.d
## One may want to save pages by /Group folders
## Option given below should appear relatively early in config.php ;
in particular, if you are using AuthUser, it must appear before you
include authuser.php.
## it should also be used before you include any other script or
recipe calling the function ResolvePageName(), and before
Internationalizations' UTF-8 and/or XLPage()
## doc : https://www.pmwiki.org/wiki/Cookbook/PerGroupSubDirectories
# $WikiDir = new PageStore('wiki.d/{$Group}/{$FullName}');

Gilles.